Starch physicochemical properties of rice accessions and their association with molecular markers

Abstract

The grain quality of rice has recently attracted a lot of attention around the world, including Africa. Rice germplasm in African gene banks has not been adequately characterized for its cooking and eating qualities which are mainly controlled by starch physicochemical properties. The aim of this study was to characterize two groups of rice germplasm from Africa and the U.S. for starch properties including gelatinization temperature (GT), apparent amylose content (AAC), and paste viscosity (RVA), and to determine molecular marker associations with these traits. Wide diversity was found for all traits studied. Variation in these traits was significantly associated with molecular markers for the alk and waxy genes which encodes soluble SS II (SSIIa) and granule bound synthase (GBSS) enzymes, respectively. Based on four previously reported waxy SNP haplotypes, 93.1 and 75.9% of the variation in AAC was explained for the U.S. and African germplasm, respectively. The classification of the genotypes by their SNP haplotypes helped to clarify the relationship between AAC and peak viscosity. The characterization of individual lines using physicochemical properties and functional markers, and the determination of marker-trait associations will facilitate the breeding of rice for grain quality in Africa and elsewhere. © 2013 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.